JPH0781605B2 - Device using electrorheological fluid - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrorheological fluid using apparatus that obtains a predetermined function by increasing or decreasing the apparent viscosity of an electrorheological fluid with an applied voltage. The present invention relates to a technique for protecting an electric power source or the like by suppressing an increase in current consumption caused by a decrease in resistance value of an electrorheological fluid due to a rise in temperature.

(Background Art) An electrorheological fluid is a fluid whose apparent viscosity changes depending on the presence or absence of the action of an electric field or the magnitude of the electric field that acts, and its apparent viscosity (hereinafter simply referred to as viscosity) by controlling the applied voltage. ) Can be controlled to be increased or decreased, and in recent years, various attempts have been made to obtain various functions by utilizing the unique properties of the vibration isolator, shock absorber, fluid valve, actuator and the like.

By the way, in an apparatus using an electrorheological fluid, such as a vibration isolator, a shock absorber, a fluid valve or an actuator (hereinafter collectively referred to as an electrorheological fluid using apparatus), they are electrically opposed to each other with the electrorheological fluid interposed therebetween. The electrodes are provided as described above, and the voltage applied between the electrodes is controlled, so that the viscosity of the electrorheological fluid is controlled to be increased or decreased. In general, when the fluid temperature rises, the electrical resistance value sharply decreases as the fluid temperature rises, and when the current density increases due to the reduction in the electrical resistance value, Does it have the property that it self-heats and the temperature of its fluid rises further, causing a significant increase in current consumption by repeating such circulation? In a device using electrorheological fluid that is used in a form in which the temperature of the electrorheological fluid can rise, the current consumption of the power supply is substantially unlimited when the temperature of the fluid of the electrorheological fluid rises. There is a problem in that the power source is overloaded and the power source is overloaded, and the power source and its peripheral devices are hindered by the overload phenomenon.

(Problems to be Solved) The present invention has been made in view of the above circumstances, and the problems to be solved are electric shock absorbers, shock absorbers, fluid valves, actuators, torque transmission devices, and the like. In an electrorheological fluid-using device that uses a viscous fluid, the current consumption of the power supply increases indefinitely even if the fluid temperature of the electrorheological fluid rises and the resistance value of the electrorheological fluid decreases significantly. To establish the technology to prevent the power supply overload phenomenon well and prevent the power supply and its peripheral devices from being hindered by the power supply overload phenomenon. is there.

(Solution) In order to solve such a problem, in the present invention, as described above, electrodes are provided so as to be electrically opposed to each other with an electrorheological fluid interposed therebetween, and a voltage application state to the electrodes is set. In an electrorheological fluid using device, which is controlled to substantially increase or decrease the viscosity of the electrorheological fluid to obtain a predetermined function, each of the electrodes is made of an insulating material having a low electrical conductivity and a predetermined thickness. By forming a resistance layer having a predetermined resistance value on each electrode surface by coating, an increase in current consumption due to a decrease in the resistance value of the electrorheological fluid due to an increase in fluid temperature is caused by an increase in the electric resistance of the resistance layer. I tried to suppress it based on this.

(Operation and Effect) In the electrorheological fluid using device according to the present invention,
Even if the fluid temperature of the electrorheological fluid rises and its electrical resistance value becomes extremely small, there is a resistance layer with electrical resistance between the electrodes that are electrically opposed to each other with the electrorheological fluid in between. The maximum value of the current consumption of is restricted based on the electric resistance of the resistance layer. Therefore, if the resistance value of the resistance layer, that is, the thickness of the resistance layer is set so that the power consumption at that time falls within the allowable capacity of the power supply, the power consumption due to the decrease in the electric resistance value of the electrorheological fluid It is possible to prevent the power supply from being overloaded due to the increase, and to prevent the power supply and its peripheral devices from being hindered by the overload phenomenon. In other words, this can greatly improve the reliability of the electrorheological fluid using device.

Further, according to the electrorheological fluid-using device according to the present invention, as described above, the maximum current consumption and thus the maximum power consumption can be specified by setting the resistance value of the resistance layer, so that the power supply can be downsized and downsized. There are advantages such as
Further, when the fluid temperature rises, it is possible to satisfactorily suppress a sharp increase in the current density of the electrorheological fluid, suppress self-heating due to the increase in the current density, and satisfactorily avoid thermal runaway of the electrorheological fluid. Since the voltage applied to the electrorheological fluid can be substantially reduced as the resistance value of the viscous fluid decreases, the apparent viscosity of the electrorheological fluid is significantly stabilized, and There is also an advantage that the function can be obtained more stably.

Moreover, according to the present invention, since each electrode is covered with the resistance layer to prevent the contact between each electrode and the electrorheological fluid, the electrodes are corroded by the moisture in the electrorheological fluid. Or, it is possible to avoid the electrode from being worn away due to contact with the electroviscous fluid,
There is also an advantage that the life of the electrode, and eventually the life of the device using the electrorheological fluid, is significantly improved.

(Examples) In order to more specifically clarify the present invention,
By switching control of the action state of the electric field on the electrorheological fluid, it is possible to effectively suppress both idling vibration and shake vibration in the same frequency range where different vibration damping characteristics are required. An example of applying the invention will be described in detail with reference to the drawings.

First, FIG. 1 illustrates an example of an automobile engine mount as an electrorheological fluid using device according to the present invention. Wherein, 10 is a block-shaped upper supporting metal fitting, and 12 is a lower supporting metal fitting having a bottomed cylindrical shape that opens upward, and are concentrically arranged so as to face each other vertically. , Are elastically connected via a ring-shaped rubber elastic body 14. And the upper support bracket
Mounting bolts 16 for fixing the metal fitting 10 to the engine side are erected on the upper surface of the 10, and the bottom wall portion of the lower support metal fitting 12 is for fixing the metal fitting 12 to the vehicle body side. The mounting bolt 18 of is set upright.

The lower support metal fitting 12 is a bottom metal fitting 20 that constitutes the bottom of the lower support metal fitting 12,
It is composed of an opening fitting 22 that constitutes the opening and two spacer fittings 24 and 26 interposed between them.
Then, the peripheral edge portion is fluid-tightly sandwiched between the bottom metal fitting 20 of the lower support metal fitting 12 and the lower spacer metal fitting 26, and a diaphragm 28 made of a rubber elastic film is disposed. A sealed space is formed between the rubber elastic bodies 14, and a predetermined electrorheological fluid 30 whose viscosity is substantially changed by the action of an electric field is enclosed in the sealed space.

In FIG. 1, reference numeral 31 denotes a rubber elastic body whose peripheral portion is fluid-tightly sandwiched between the opening fitting 22 and the spacer fitting 24.
A protective rubber film made of NBR or the like integrally provided on the inner surface portion of 14 and provided to protect the rubber elastic body 14 from the electrorheological fluid 30.

In an enclosed space in which the electrorheological fluid 30 is sealed, an outer peripheral edge portion is fluid-tightly sandwiched between the spacer fittings 24 and 26, and an annular orifice forming member 32 is arranged. A disk-shaped movable plate 36 is provided, which is held by an annular groove formed on the inner peripheral surface of the member 32 so as to be movable along the peripheral edge by a predetermined amount in the plate thickness direction. The movable plate 36 divides the closed space containing the electrorheological fluid 30 into the pressure receiving chamber 38 on the rubber elastic body 14 side and the equilibrium chamber 40 on the diaphragm 28 side.

The orifice forming member 32 that holds the movable plate 36 can be regarded as a substantially electrically insulating material with respect to the electrorheological fluid 30, such as a fluorine resin, and usually has an organic solvent resistance of about 10 ¹⁵ Ωcm or more in volume resistivity. Upper orifice forming member 42 made of the material
The lower orifice forming member 44, the inner sealing member 46 and the outer sealing member 48 are integrally assembled and configured, and have an annular space inside thereof. Then, as shown in FIG. 2, through holes 50 and 52 are formed in different phase devices of the upper orifice forming member 42 and the lower orifice forming member 44, respectively, and the pressure receiving chamber is formed in the annular space. Two long and short orifice passages 54 and 56 are formed to connect the 38 and the equilibrium chamber 40, and the electrorheological fluid 30 in the pressure receiving chamber 38 and the equilibrium chamber 40 mutually flows through the two orifice passages 54 and 56. I'm supposed to get it.

Here, as shown in FIG. 1, in the orifice passage 56 on the side of the shorter flow path length, the orifice passage 56 is opposed to the vertically opposed wall surfaces at a constant distance. A pair of plate electrodes 58, 60 over substantially the entire length of
Is provided, and a booster (power source) 6 is provided on the plate electrodes 58 and 60.
2 is connected so that a predetermined high DC voltage can be applied between the electrodes 58 and 60, and as shown in FIG. 3, the electrodes 58 and 60 have the same thickness. In a state of being covered with, a resistance layer 64, 66 having a predetermined resistance value and made of an insulating material having a low conductivity, such as a thermosetting resin such as a phenol resin, a thermoplastic resin, an insulating varnish, mica, or ceramics.
Even if the electric resistance value of the electroviscous fluid 30 is significantly reduced due to the rise of the fluid temperature,
The current consumption of 62, that is, the power consumption, is
Based on the electric resistance of 6, the booster device 62 can be suppressed to have an allowable capacity or less. The resistance layers 64 and 66 cover the electrodes 58 and 60 by a method according to the material of each.

In such an engine mount, when a voltage is not applied between the electrodes 58 and 60, the electric field is not applied to the electrorheological fluid 30 located in the orifice passage 56, and the electric viscous fluid 30 is located in the orifice passage 56. Electrorheological fluid 30
Viscosity of the electrorheological fluid located in the orifice passage 54
As low as 30's, it is kept low. Therefore, in the state where no voltage is applied, the electrorheological fluid 30 is mainly allowed to pass through the orifice passage 56 having a small flow resistance.

On the other hand, when a voltage is applied between the electrodes 58 and 60, the viscosity of the electrorheological fluid 30 located in the orifice passage 56 is substantially (apparently) significantly increased, and the flow resistance of the orifice passage 56 is significantly increased. To do. Therefore, in this case, the electrorheological fluid 30 mainly flows through the orifice passage 54 having a long flow passage.
Will be able to pass through.

That is, in such an engine mount, the electrodes 58,6
By controlling the state of voltage application to 0, the orifice passage through which the electrorheological fluid 30 passes can be selected substantially arbitrarily. Therefore, the orifice passage 54 is set to a frequency range (10) where idling vibration and shake vibration occur. ~ 30Hz
While tuning the orifice passage 56 to a frequency range higher than the frequency range, the electrodes 58, 60 are tuned when the vehicle is running and idling.
By controlling the application of voltage to the switch, low damping and high dynamic spring characteristics can be achieved during idling, and idling vibration can be blocked well, while high damping and low dynamic spring characteristics can be achieved during running. As a result, the shake vibration can be satisfactorily damped, and by this, a good vibration-damping effect can be exhibited for both idling vibration and shake vibration in the same frequency range that require different vibration damping characteristics. It will be.

In addition, in such an engine mount, the movable plate
Based on the movement of 36 in the plate thickness direction, vibrations in a high frequency range such as muffled sound are effectively blocked.

By the way, when the temperature of the electrorheological fluid 30 rises, the electric resistance value remarkably decreases, and for example, it decreases to less than two digits of that at room temperature. Therefore, when the resistance layers 64 and 66 are not present, the electrical resistance between the electrodes 58 and 60 is significantly reduced when the fluid temperature of the electrorheological fluid 30 rises, and the output current of the booster 62 (consumption Current) increases remarkably, the power consumption of the booster 62 becomes larger than the allowable capacity thereof, causing an overload phenomenon, and the overload phenomenon may damage the booster 62 and its peripheral devices. Occurs.

However, in the engine mount of the present embodiment, as described above, the resistance layers 64 and 66 are arranged so as to cover the electrodes 58 and 60, respectively, and the electric resistance of the resistance layers 64 and 66 is between the electrodes 58 and 60. Since it is in the state of being intervened in
Even if the electric resistance value of the electrorheological fluid 30 is significantly reduced, the electric resistance between the electrodes 58 and 60, that is, the load resistance of the booster 62 is equal to or less than the electric resistance values of the resistance layers 64 and 66. But its output current (consumption current) is also resistance layer
It will be suppressed below the current value specified by the electrical resistance value of 64, 66. Therefore, it is possible to satisfactorily avoid that the booster device 62 overloads due to the output current of the booster device 62 increasing substantially indefinitely, and the booster device 62 and its peripheral devices are damaged by the overload phenomenon. Such a situation can be satisfactorily avoided.

Further, in the engine mount of this embodiment, as described above, the maximum current consumption (maximum power consumption) of the booster 62 is defined by the resistance layers 64 and 66, so that the current consumption increases substantially without limit. In consideration of this, it is not necessary to increase the capacity of the booster (power supply) 62.
Is advantageous in that it can be advantageously made smaller in capacity and size, and the limit of the current density of the electrorheological fluid 30 is well suppressed by the regulation of the maximum current consumption, and the current Thermal runaway due to self-heating of the electrorheological fluid 30 due to the increase in density is well avoided,
Further, since the applied voltage to the electrorheological fluid 30 is substantially reduced due to the decrease in the electric resistance value of the electrorheological fluid 30, the apparent viscosity of the electrorheological fluid 30 when the fluid temperature rises, and thus the electrorheological fluid 30. There is also an advantage that the vibration isolation characteristics of the engine mount when voltage is applied when the fluid temperature rises is significantly stabilized.

Further, in the engine mount of this embodiment, as described above, the surfaces of the electrodes 58 and 60 are covered with the resistance layers 64 and 66, respectively, so that the electrodes 58 and 60 do not come into direct contact with the electrorheological fluid 30. Therefore, the water in the electrorheological fluid 30 may cause the electrodes 58 and 60 to be corroded early, or the electrodes 58 and 60 may be worn due to contact with the differential particles in the electrorheological fluid 30. This is avoided in advance, and therefore, there is also an advantage that the life of the electrodes 58, 60 is significantly extended and the life of the engine mount can be significantly extended.

The resistance value of the resistance layers 64, 66 varies depending on the characteristics of the electrorheological fluid 30 and the like, but if it is too large, the shared voltage of the resistance layers 64, 66 at room temperature becomes significantly large, In order to apply the desired voltage to the electrorheological fluid 30 at room temperature, there is a problem in that the output voltage of the booster 62 must be significantly increased, and if it is too small, the fluid temperature of the electrorheological fluid 30 will increase. It becomes difficult to keep the current consumption small when the electric resistance value becomes small and the electric resistance value becomes small. 0.1 of the electric resistance value of the electrorheological fluid 30 located between
It is set to about 10 times, more preferably about 1 to 5 times. That is, the thickness of each of the resistance layers 64 and 66 is set so that the resistance value is within the range.

As described above, one embodiment of the present invention has been described in detail, but this is a literal example, and the present invention should not be construed as being limited to such a specific example, within a range not departing from the gist thereof. Needless to say, the present invention can be carried out in various modified, modified, and improved modes.

For example, in the above-described embodiment, the resistance layers 64 and 66 have the same thickness, but the resistance layers 64 and 66 do not necessarily have to have the same thickness, and the resistance layers 64 and 66 are mutually different. It is also possible to use different insulating materials, and further, to provide the resistance layers 64 and 66 only on the surfaces of the electrodes 58 and 60 facing each other.

Further, the present invention is not necessarily limited to the engine mount of the illustrated structure, and an engine mount using an electrorheological fluid other than the engine mount of the illustrated structure, or an electrorheological fluid using device other than the engine mount, for example, It is also possible to apply the present invention to a shock bubber, a fluid valve, an actuator, a torque transmission device, or the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing an engine mount as an example of an electrorheological fluid using device according to the present invention.
1 is a plan view showing an assembly of an orifice forming member and a movable plate of the engine mount shown in FIG. 1, and FIG. 3 is a cross-sectional view for explaining an electrode structure of the engine mount shown in FIG. . 30: Electrorheological fluid, 58, 60: Electrode 62: Booster (power supply) 64, 66: Resistance layer

Claims (1)

[Claims] Claims: 1. Electrodes are provided so as to be electrically opposed to each other with an electrorheological fluid sandwiched therebetween, and the state of application of a voltage to the electrodes is controlled to substantially increase or decrease the viscosity of the electrorheological fluid. In the device using electrorheological fluid to obtain the function of, each of the electrodes is covered with an insulating material having a low conductivity and a predetermined thickness, and a resistance layer having a predetermined resistance value is formed on each electrode surface, An electrorheological fluid using device, characterized in that an increase in current consumption due to a decrease in resistance value of the electrorheological fluid due to a rise in fluid temperature is suppressed based on the electrical resistance of the resistance layer.